From the related art, the reduction of noise due to a jet flow injected from a jet flow nozzle has been proposed in a jet engine.
For example, Patent Document 1 discloses a jet flow nozzle which includes a mixer serving as an obstacle for a flow path of the jet flow. The jet flow nozzle including the mixer slows down the jet flow (a core flow) injected via a nozzle outlet end by the mixer, makes the velocity of the jet flow close to that of an external air flow, facilitates the mixing of the jet flow and the external air flow, and promotes the reduction of noise.
More specifically, by facilitating the mixing of the jet flow and the external air flow, a vortex formed near the nozzle outlet end is finely dispersed, the occurrence of a large vortex serving as a main cause of noise is suppressed, and the reduction of noise is promoted.
However, an effect of noise reduction of the jet flow nozzle including the mixer described in Patent Document 1 was not sufficient.
Thus, as described in Non-Patent Documents 1 to 3, a method of promoting the reduction of noise by placing a plurality of micro jet nozzles around the nozzle outlet end and injecting the air flow from the micro jet nozzles toward the core flow has been suggested.